1. Field of the Invention
The present invention relates to a wet-etching facility for manufacturing semiconductor devices, and more particularly, to a wet-etching facility for manufacturing semiconductor devices for easily removing the impurities with the used surface of the wafer faced down.
2. Description of the Related Art
Generally, the etching process in the semiconductor devices fabrication processes is a process to selectively remove the most upper layer of the wafer through a photo resist layer having a certain pattern after exposure and development, etc. Normally, a wet-etching or dry-etching method can be used.
The wet-etching process is performed by immersing the wafer into a bath having a certain amount of chemical disposed therein, and causing a chemical reaction with a contacted surface of the wafer so that the unnecessary portion of the wafer is etched by the chemical.
FIG. 1 shows a conventional wet-etching facility to perform the wet-etching process in the semiconductor devices fabrication process.
As shown in FIG. 1, the conventional wet-etching facility comprises a box-shaped bath 110 storing a chemical 3 therein, a chemical supply part (not shown) to supply the chemical 3 to the bath 110 through a chemical opening 110a formed on the bottom of the bath 110, a chemical container 120 to collect the chemical 3 overflowing over the bath 110, a chemical discharge part (not shown) to discharge the chemical 3 collected in the chemical container 120 to the outside through a discharge opening 120a formed on the bottom of the chemical container 120, and a wafer guide 130 to fix the wafer 1 to the slots 130a having a plurality of wafers 1 vertically fit thereinto, the slot 130a aligned with a constant interval, and to place them the wafers 1 into the chemical 3 using a suitable device, such as a robot arm 136.
In the conventional wet-etching facility having a construction as above, the chemical supply part supplies the chemical 3 such that the chemical 3 overflows out of the bath 110 via the chemical opening 110a formed on the bottom of the bath 110, and the flow of the chemical 3 is formed on the surface of the wafer 1 so as to facilitate the chemical reaction between the chemical and the wafer 1.
However, as shown in FIG. 2, since the used surface of the wafer 1 is placed vertically, and the etched impurities 2 of the wafer 1 by the chemical cannot be completely removed therefrom resulting in an amount of etched impurities 2 accumulating on the bottom of the etch groove by gravity. This accumulation of etched impurities 2 is one of the main reasons why a malfunction may occur in the following process and also results in inferior wafers being generated due to the impurities being attached on the used surface of another wafer.
In addition, since the plurality of wafers 1 are vertically aligned inside the slots, there is a possibility that on occasion the upper end of one wafer 1 touches the other wafers, and they are broken since the wafers are shaken during the transfer.
In addition, since a plurality of wafers 1 are horizontally loaded during a transfer, there is required an extra wafer vertical-aligning apparatus to vertically rotate the wafers when the wafers are converted to be into a vertical state. Therefore, the facility is complicated, and productivity is decreased because of the time waste by the wafer vertical-aligning.
In addition, since the bath is box-shaped, and the flow of the chemical is directed from the lower side to the upper side, as anti-gravity direction, particle vortex occurs inside the bath, particularly, on the corners therein or maintenance of chemical thereby resulting in difficulty of the uniform process for wafers.